HYPERPICO : Une approche instrumentale et méthodologique avancée dédiée à la conservation préventive

In the face of climate change and the need for an energy transition toward greater sustainability, the diagnostic tools available for preventive conservation—particularly in historic residences and exhibited collections—are becoming increasingly limited. New environmental conditions—including rising temperatures, humidity, and precipitation, as well as unpredictable and sudden fluctuations of significant magnitude—no longer allow for the conservation and resilience strategy of a historic residence to be based solely on the historical record of macroscopic environmental measurements. Indeed, historic residences are facing an increase in deterioration of collections and interiors, despite the significant conservation measures implemented (indoor climate control, window protection with filters, risk management plans, etc.), which appear to be correlated with the rise in atypical weather events. In this context, the HypErPICO project aims to implement innovative techniques for in situ multidimensional (spatial and spectral) measurements and to develop data processing tools to enhance existing decision-support tools. The scientific challenge is to establish a three-dimensional mapping of the physical characteristics of spaces and objects and to monitor them, from the molecular scale to the structural scale. This work aims to develop a new hyperspectral imaging system combined with 3D reconstruction to identify, over the long term, the thresholds of irreversible physicochemical transformation of the objects and the decorative elements that constitute them. In addition to multispectral analysis, goniometric analysis requires precise spatial localization of objects to ensure their monitoring over long periods (several years). Two rooms in the Palace of Versailles—the Queen’s Bedroom and the Salon de Mercure (selected based on their orientation and statistical representativeness)—as well as the furnishings and decorative elements within them are studied at a rate of four seasonal measurements per year. The objective is to identify the various objects and classify the materials used in the furniture and walls of the rooms under study in order to detect any changes over time and establish a diagnosis correlated with sensor data readings (temperature, humidity, etc.). Indeed, different types of materials will be subject to different types of temporal variations or degradation, which will be documented. At the same time, to enable the identification of these variations and any potential degradation—whether reversible or irreversible—tests must be conducted on samples to determine the characteristic spectral signatures that can subsequently be identified in the in situ hyperspectral data. In this context, one of the major challenges involves monitoring the moisture content of fabric-based objects and wooden furniture, as these are the first to be affected by changes in humidity—whether through geometric changes, structural degradation, or even biological infestations. This research is part of the EPICO (European Protocol in Preventive Conservation) program, launched in 2014 by the Établissement Public de Versailles (EPV), and is supported and funded by the Fondation des Sciences du Patrimoine. The new goniometric-hyperspectral system, consisting of two cameras covering the 400–1,700 nm spectrum (visible and near-infrared) and a LiDAR for geospatial data, is funded under the Equipex+ Espadon program.